使用Retrofit的多部分POST请求

// 创建Retrofit实例
Retrofit retrofit = new Retrofit.Builder()
        .baseUrl("https://api.example.com/")
        .build();

// 创建API接口
ApiService apiService = retrofit.create(ApiService.class);

// 创建文件RequestBody
File file = new File("path/to/file");
RequestBody fileRequestBody = RequestBody.create(MediaType.parse("multipart/form-data"), file);

// 创建文本RequestBody
RequestBody textRequestBody = RequestBody.create(MediaType.parse("text/plain"), "Hello, world!");

// 创建多部分RequestBody
MultipartBody.Part filePart = MultipartBody.Part.createFormData("file", file.getName(), fileRequestBody);
MultipartBody.Part textPart = MultipartBody.Part.createFormData("text", "example", textRequestBody);

// 发送多部分POST请求
Call<ResponseBody> call = apiService.uploadFile(filePart, textPart);
call.enqueue(new Callback<ResponseBody>() {
    @Override
    public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
        // 请求成功处理
    }

    @Override
    public void onFailure(Call<ResponseBody> call, Throwable t) {
        // 请求失败处理
    }
});